The invention relates to a unit of an electric lamp and a reflector, comprising:
a moulded reflector body provided with a reflector portion having a concave reflecting surface with an optical axis, and integral therewith a hollow neck-shaped portion surrounding said optical axis; PA1 an electric lamp provided with a light-transmitting lamp vessel which is sealed in a vacuumtight manner and which has a cavity in which an electric element is arranged and which lamp vessel is provided with a first and a second mutually opposing end portion with seal, through which seals respective current conductors connected to the electric element issue from the lamp vessel to the exterior, PA1 the electric lamp being fixed in the reflector body with the first end portion inside the neck-shaped portion, while the cavity lies within the reflecting portion and the electric element is on the optical axis; PA1 a lamp cap having an electric contact to which a current conductor is connected, which lamp cap is fixed to the neck-shaped portion of the reflector body.
Such a unit of electric lamp and reflector is known from U.S. Pat. No. 4,423,348.
Units of this type may be used for projection purposes, for example, film or slide projection, but also in projection TV devices. If the light generated by the lamp is to be efficiently used, it is necessary for the lamp to be positioned with its electric element on the optical axis of the reflector portion. Variations in the position of this element in the lamp vessel render a wide neck-shaped portion necessary so as to allow lateral displacements of the lamp. A wide neck-shaped portion, however, reduces the size of the reflecting surface of a reflector body of a given shape and dimension.
A further loss of reflecting surface area occurs in that the reflector body must have such a shape as to be clearing. "Clearing" means that the reflector body must be capable of being removed from the mould in which it was formed. This is only possible when a displacement of this body in the open mould is possible, which leads to a clearance between the mould and the body on all sides. Known reflector bodies for this purpose widen towards the reflecting portion. If there should be sufficient space for a lateral displacement of the lamp at the free end in the neck-shaped portion, this neck-shaped portion should accordingly be extra spaceous adjacent the reflecting portion.
According to the Application EP 92 201 469 not previously published, the neck-shaped portion is subdivided into two longitudinal parts, which parts are joined together during the assembly of the lamp with the reflector. Since the neck-shaped portion integral with the reflecting portion is short here, the widening towards the reflecting portion is correspondingly small. A disadvantage, however, is that the number of components to be assembled has increased owing to this subdivision.